In the state of the art, a problem which has not been correctly solved is that the drawing sectors are not displaced congruently, according to corresponding points, with the drawing sectors of the chock if the axes remain correspondent.
JP-A-57195513 discloses a device to perform a cross section of rolls smoothly, by providing chock holding devices to both sides of the roll chocks along a rolling direction and by rocking both rocking pieces of the devices to opposite directions by equal quantities respectively by making the eccentric pins as the rocking centers. In particular, two jacks are actuated respectively in opposite directions by equal quantities. At the side of a first jack, the movement of the latter is transmitted to a corresponding eccentric pin through a slide block, a link, a lever, and a rotary shaft; at the side of a second jack, the movement of it is transmitted to another corresponding eccentric pin in the same manner. Accordingly the two eccentric pins are rotated respectively in opposite directions by equal quantities to move rocking pieces in opposite directions by equal quantities respectively. Against the movements of such rocking pieces at an operation side, rocking pieces at a driving side move reversely to the operation side, and in opposite direction by the same quantity respectively in order to make the roll axis cross an horizontal imaginary line which intersects the rolling direction perpendicularly. This known device is complicated and cumbersome due to the use of eccentric means.